Writh the BBC adapting Hilary Mantel’s Wolf Hallfor TV, the RSC preparing a stage version and the Mantel books themselves still the upmarket beach read du choix, Thomas Cromwell is the man of the moment. It is a pity, really, that he was beheaded nearly 500 years ago and his head stuck on a pike on London Bridge: he could have been a smash on the after-dinner circuit.

What fascinates us about Cromwell now is evident in Friday’s film’s full title: Henry VIII’s Enforcer: the Rise and Fall of Thomas Cromwell (BBC Two, Friday). Seen through the prism of modern politics and its mangling of language, suddenly Cromwell can be cast as an “enforcer”, or a brilliant “operator”, rather than a thug or a schemer. It used to be quite simple. Cromwell dissolved monasteries like most people dissolve aspirin, drove a wedge between England and Rome and put paid to Anne Boleyn. With the binary view of history that made primary school so much fun, Cromwell was a panto baddie.

But Mantel’s books have brought about a re-appraisal, and lo and behold it now looks like poor Cromwell has been a little hard done by. Mantel’s books are, of course, historical fiction, which is where Professor Diarmaid MacCulloch stepped in last night – windmilling into a room full of trusty certainties with the sword of historical fact to tell us that everything we thought we knew about Cromwell was poppycock.

The unfortunate thing about revisionism, however, is that it is an ever-turning wheel - all history turns out to be endlessly revisable. If the question is, “Cromwell: visionary or thug?” the answer will almost invariably turn out to be “thugonary”. So it proved under MacCulloch’s analysis – on the one hand Cromwell was actually motivated by genuine religious zeal. But on the other he was a wily operator who conspired to kill a queen. And we’re none the wiser.

Another thing that the documentary taught us was never to underestimate the power of a potent image. Holbein’s portrait of Cromwell makes him look like a grumpy grocer with a cowpat on his head. I may lack the historical grounding of MacCulloch, but I reckon that that one picture has done more to cement Cromwell’s image as a Tudor version of Malcolm Tucker than any number of biographies.

The fact that one image is so persuasive also reminded us that the problem of trying to tell Tudor history on television – in fact the problem with trying to tell any history on television before about 1920 – is that they didn’t have film cameras then. Delightful as it was to watch the Professor strut around various Cambridge colleges and monastic ruins, Henry VIII’s Enforcer struggled when it came to pictures to go with the words. In a laudable attempt to address this problem, the producers invented something that looked like your eight-year old’s school project, featuring strips of Tudoresque illustrations scrolling back and forth across the screen. And when you have Hilary Mantel bringing Cromwell and his world to life every which way you look, that’s not good enough.